The world is reeling from the contradictory messages President Donald Trump and his administration are churning out on North Korean leader Kim Jong Un’s nuclear threat. That includes Trump tweeting on Oct. 1 that Rex Tillerson, his own secretary of state, was “wasting his time” trying to negotiate an end to the North Korean conflict, and tweeting on Oct. 7 that after 25 years of failed talks, “only one thing will work!”

In the midst of the policy whiplash from the top, the Pentagon and State Department are quietly chugging away at the ground level, where the foreign policy of Trump’s Twitter feed is competing with foreign policy of the rest of the U.S. government.

U.S. military leaders, in particular, continue to insist that any engagement with the North Koreans must be led by the country’s diplomats.

The American effort is “diplomatically led,” Defense Secretary James Mattis told an annual U.S. Army conference in Washington on Monday. It’s an “economic sanction-buttressed effort to try to turn North Korea off this path,” Mattis said.

“What does the future hold? Neither you nor I can say, so there’s one thing the U.S. Army can do, and that is you’ve got to be ready to ensure that we have military options that our president can employ, if needed,” he added.

Mattis’s line echoed remarks he has made for weeks about the military’s willingness to take a back seat to the State Department. But the Pentagon’s top generals say they have no illusions what the future might look like if hostilities were unleashed.

“A full-blown war on the Korean Peninsula will be horrific by any stretch of the imagination,” U.S. Army Chief of Staff Gen. Mark Milley told reporters Monday. But equally horrific, he said, would be an attack on the United States.

“It would be horrible, there’s no question about it, but so would an intercontinental ballistic missile striking Los Angeles or New York City. That would be equally horrible.”

Top Republican lawmakers are wringing their hands over the lack of any realistic military option even as Trump appears to be counting on one to bring Pyongyang to reason.

“There is no viable military option. It would be horrific,” Sen. Ron Johnson (R-Wis.) said on CNN.

Behind the scenes, the State Department is working bit by bit and country by country to cut off North Korea’s lifelines to the outside world. Under the auspices of what the State Department dubs a new “pressure campaign,” 20 countries have cut back diplomatic relations or moneymaking operations of the Hermit Kingdom, the Wall Street Journalreported. Italy, Spain, Kuwait, Peru, and Mexico all booted North Korea’s ambassadors out of their countries in recent months after Washington warned they were using their embassies as a front to ship weapons, contraband, and cash to Pyongyang.

Other countries, including Kuwait and Qatar, agreed to slash economic ties and North Korean foreign workers programs to tighten the economic noose around the North Korean regime. And as Washington lifted decades-old sanctions on Sudan for the first time on Oct. 6, Sudan agreed to not pursue new arms deals with Pyongyang.

Pyongyang, meanwhile, remains defiant.

On Monday, North Korean state news agency Minju Choson issued a quintessentially North Korean threat to South Korea as the military showdown with the United States and its Asian allies continued: “The ridiculous farce of the puppet forces only provokes derision and censure of people and will only bring earlier the miserable end of the imbeciles going helter-skelter just like a puppy fearless of a tiger,” the newspaper said, as tracked by North Korean news aggregation website KCNA Watch.

Photo credit: Spencer Platt/Getty Images

Robbie Gramer is a diplomacy and national security reporter at Foreign Policy. @robbiegramer